Metal Polishing MythsMany of the following statements are controversial and disagree with popular polishing practices. We've found that some polishing myths are deliberately perpetuated by the industry and others are just common errors of judgment. Here is the inside story that the manufacturers don't want you to know.
All Metal Polishes are the Same.
Most definitely they are not. Anti-oxidants, enhancers, grime removers, inhibitors, slip agents, etc., they vary, sometimes enormously, from brand to brand.
All Metal Polishes Protect the Finish.
Polishing may protect a surface to some degree, however many metal polishes contain ammonia or anhydrous derivatives. In fact this is the industry standard, and has been proven to cause premature aging of many alloys, especially brass and copper. Minute cracks and fissures appear after excessive use of ammoniates or anhydrous products. These harsh chemicals will actually increase tarnishing and cause metals to lose their luster more quickly. Therefore, the manufacturers sell more product.
Polishing with correctly formulated products will increase the life span of the metal, whereas the use of ammonia and anhydrous products has been proven to do the opposite. Anhydrous chemicals will dissolve Zinc, a major component of brass, and nearly always present on aluminum castings. Zinc is also often used to stop steel from corroding. Anhydrous chemicals can destroy these materials.
A few manufacturers use mild acids instead of ammoniates or anhydrous. These acids etch the surface to remove oxidation, which will also damage the metal.
All Metal Polishes can be Used on Any Metal.
Most definitely not. Stainless steel and chrome polishes cannot be used on soft metals such as gold, silver, platinum, pewter, copper and precious pieces.
If the formula is aggressive enough to cut stainless it will gouge soft metals and remove unnecessary material. If the polish is safe for finishing aluminum, it will have little effect on chrome, bronze or stainless steel.
Paste Metal Polishes are Better than Liquid Polishes.
This is totally untrue. Liquid polishes tend to perform better because they allow you to use the oxidation you're removing as an abrasive. Paste polishes tend to be harder to wipe off, especially if they are allowed to dry. They can leave a large amount of white residue in small grooves or cracks. Liquid metal polishes dry to a powdery residue which is much easier to remove, and the fast acting formulas (containing mild abrasives) perform to the same, or higher level than typical paste formulas.
Polished Surfaces Should be Protected with a Clear Coating.
Definitely not. Lacquer and clear coatings discolor, crack and become porous with age. Pieces subjected to an ocean environment, or stored for many months should be protected a liquid polymer sealant.
Show vehicle bright work can be waxed for tarnish protection and to also improve the luster on soft metals. The decision to wax stainless would depend on the type of finish. It would be an advantage on stainless with a high shine, but unnecessary on a satin finish.
Chrome does not require a protectant. A quick wipe down between polishes will suffice. Any metal subject to heat should be completely wax and sealant free.
Jeweler's Rouge can be Substituted for Metal Polish.
Sorry, true jeweler's rouge only comes in one cutting level, and is much too fine to tackle the many levels of vehicle metal polishing. Jeweler's rouge was developed for the ultra fine polishing of jewelry.
Many manufacturers call all bar colors, jeweler's rouge - but 'rouge' is French for 'red'. Jeweler's rouge is red because it contains ferric oxide. If it doesn't contain ferric oxide, it's not rouge. Green and white bars are abrasive compounds, which are too coarse to be used on soft metals.
Fine Polishes Will Not Cut.
The ability for a polish to "cut" depends on the shape of its crystals or particles, not necessarily it's size. A medium size, spiked abrasive will tumble and dig. However, a large round crystal won't leave a deep scratch.
A large hard abrasive may also be brittle. It will cut once and lose its edge, while a softer small abrasive will hold its edge and keep on cutting. Many smaller abrasives have wedge shaped edges protruding from triangular crystals. These can easily slice through an oxidized layer of metal.
Stainless Steel does not Need Polishing.
A common misconception is that stainless steel is stain proof. This is false. It merely stains less. Austinitic stainless steel doesn't tarnish or discolor easily, but martinsitic stainless will. All stainless takes on bleed marks and stains from contact with other metals and overheating.
All Metals can be Polished.
Some polishes are advertised as a mag and aluminum polish. This is misleading as you cannot produce a high shine on magnesium. You can clean and remove oxidization from magnesium, but you cannot polish it. Even producing a shine on mag alloys depends on the amount of magnesium content. Modern alloy wheels are usually clear coated.